LONDON - Britain is bracing for clashes with right-wing extremists and possible copycat terror attacks after the brutal slaying of a young soldier.

London's Metropolitan Police said more than 1,000 officers will be sent to potential trouble spots with armed response units. Only a fraction of Britain's police officers are armed.

Wednesday's bloody attack was captured on video by passersby and made for gruesome viewing — one man is seen with his hands stained red and holding two butcher's knives as he angrily complained about the British government and troops in foreign lands. A lifeless body is seen on the street behind him.

Terror analysts say the attackers wanted the publicity to inspire copycat attacks, and that they are already seeing an increase in chatter on extremist sites calling for such attacks.

"We can see the tempo being raised," said Maajid Nawaz, a former jihadist who is now with the London-based anti-extremist Quilliam Foundation.

"One of the reasons why these guys acted in this theatrical way was because of the propaganda effect so others would be inspired to do the same thing. The nature of these attacks are that they are so easy to do, and we have definitely seen an increase in chatter calling for such things since the attack."

Alastair Grant, Associated Press - Ap

Britain's Prime Minister David Cameron speaking to the media outside 10 Downing Street in London, Thursday, May 23, 2013. The British government's emergency committee met Thursday after two attackers butchered a British soldier in a daylight attack in London that raised fears terrorism had returned to the capital. Prime Minister David Cameron says there are strong indications it was an act of terrorism, and his top advisers will be examining the potential security implications of the attack, which took place near a military barracks in the Woolwich area of the city. Police Thursday confirmed the dead man was a serving soldier and said his identity will not be released yet at his family's request. They said a post-mortem examination will be conducted later Thursday.

A British government official who spoke on condition of anonymity because he was not authorized to speak about the ongoing investigation, confirmed the increase in chatter since Wednesday's attack but said no specific or credible plots had been detected at this point.

Britain's terror threat level has remained unchanged at "substantial" — the middle of five possible rankings.

Right-wing extremists, meanwhile, said they would be holding demonstrations over the coming weeks. Several dozen gathered the night of the slaying to protest.

Britain's domestic spy agency of MI5 has long warned of the difficulties in predicting self-starter attacks, or attacks that are inspired — not necessarily organized — by larger groups.

With the weakening of al-Qaida's leadership structure in Afghanistan and Pakistan, there has been an increase in lone-wolf attacks, which are low-tech and relatively easy to pull off.

Both suspects in the soldier's killing were on the agency's radar for as long as six years. Video footage showed one of the men at a 2007 rally with Anjem Choudary, the former leader of the banned extremist group al-Muhajiroun.

But the men weren't necessarily the focus of any specific investigation, said the British official who spoke on condition of anonymity. There has to be compelling intelligence to suggest a real threat before suspects are put under surveillance.

"It is a democratic right to protest in this country," said the British official. "Not everyone who shows up at a demonstration, even though they may say or believe in things that we don't, will turn to violence."

President Donald Trump's national security adviser said Saturday there was "incontrovertible" evidence of a Russian plot to disrupt the 2016 U.S. election, a blunt statement that shows how significantly the new criminal charges leveled by an American investigator have upended the political debate over his inquiry.